pretty much, has a horse in this race, but your horse is your equation? >> i'm an econometrician, not a pundit, right? so the horse you're interested in, okay, is my equation. but i have another side of me which i'm not talking to you about, which is what i personally would like to see. >> reporter: and you're not going to tell me what that is. >> i'm not going to tell you what that is, no. >> reporter: how accurate has the model been? >> my interest is in vote share, and on that metric, looking at the predictions the average error over these elections is 3.6%. >> reporter: 3.6%? >> that's correct. within this margin of error, yes. >> reporter: as it turns out, that's about the same margin of error as for the second major source of presidential predictions, the polls. >> in 2008, we polled in a bunch of swing states, we got within three points of president obama's actual margin-- ohio, pennsylvania, florida, colorado, wisconsin. >> who do you think would do a better job on the economy, mitt romney or barack obama?